Katharina Buczek
So, it has become clear that ketamine is a worthwhile treatment avenue to explore, hence why the University of Pennsylvania research team decided to conduct an experiment on mice aimed at analyzing the mechanisms which underpin ketamine-induced dissociative states.
In the experiment, the mice received a dose of ketamine that was anticipated to result in dissociative states.
Then, the researchers observed the animals’ brain activity by utilizing two-photo microscopy– or an imaging technique that enables researchers to continuously analyze specific neurons or individual cells inside an animal’s brain for several minutes or days.
According to Cichon, they also expressed GCaMP6– a fluorescent calcium sensor– in order to image neuronal activity among specific cell types.
“This protein changes its fluorescent intensity depending on the calcium concentration in the neuron, which rises and falls with neuronal firing,” Cichon said.
And by observing the fluorescent signal fluctuations among individual neurons, the researchers were then able to image how ketamine is able to alter the neuronal activity pattern of specific individual neurons.
Then, upon analyzing these neuronal recordings, the researchers ultimately found that ketamine essentially “switched” the cortical activity within the animals’ brains.
In other words, neurons that were previously silent were spontaneously activated; meanwhile, neurons that were highly active suddenly became suppressed.
Of course, interpreting these findings is far from an easy feat– most notably because it is extremely difficult to determine whether or not the mice experienced dissociative states.
Nonetheless, the research team successfully identified two distinct cortical neuron populations. The first is active during wakefulness, then suppressed following ketamine treatment, and the second is typically silent but activated following administration of the drug.
And moving forward, these findings could help open the door for new discoveries regarding the neural processes that result in the brain becoming disconnected from the environment while still having subjective experiences.
